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Thermal Modeling of DC/AC Inverter for Electrified Powertrain Systems

FCA US LLC-Meng Li, Bruce Geist
Gotion, Inc.-Fan He
  • Technical Paper
  • 2020-01-1384
To be published on 2020-04-14 by SAE International in United States
A DC-to-AC main Power Inverter Module (PIM) is one of the key components in electrified powertrain systems. Accurate thermal modeling and temperature prediction of a PIM is critical to the design, analysis, and control of a cooling system within an electrified vehicle. PIM heat generation is a function of the electric loading applied to the chips and the limited heat dissipation within what is typically compact packaging of the Insulated Gate Bipolar Transistor (IGBT) module inside the PIM. This work presents a thermal modeling approach for a 3-phase DC/AC PIM that is part of an automotive electrified powertrain system. Heat generation of the IGBT/diode pairs under electric load is modeled by a set of formulae capturing both the static and dynamic losses of the chips in the IGBT module. A thermal model of the IGBT module with a simplified liquid cooling system generates temperature estimates for the PIM. Temperatures of chips, baseplates, and sinks are predicted from electric input loads. A case study is provided in wh ich the PIM thermal model is coupled with…

Nonlinear Iterative Optimization Process for Multichannel Remote Parameter Control

SAE International Journal of Vehicle Dynamics, Stability, and NVH

Meng Li, Yong Zhang
  • Journal Article
  • 10-03-03-0015
Published 2019-10-14 by SAE International in United States
In this article, compared with traditional Remote Parameter Control (RPC), the iterative process is improved based on linear transfer function (TF) estimation of the nonlinear dynamic system. In the improved RPC, the iteration coefficient is designed according to the convergence condition of the nonlinear iterative process, so that the convergence level, convergence speed, and iteration stability could be improved. The difference between the traditional and the improved RPC iterative process is discussed, the RPC iterative process of the nonlinear system is analyzed, and channel decoupling for Multi-Input Multi-Output (MIMO) system based on eigen-decomposition of the system TF and linear TF estimation is introduced. It assumes that the eigenvector matrix of the system TF remains the same, and the linear TF in the iterative process is estimated and updated, which is used for iterative calculation. The method for iteration coefficient is designed according to the nonlinear system convergence condition of the iterative process. The whole theory is verified on a two-channel electrohydraulic servo system and a lightweight motorcycle. The optimization strategy can be used not only…
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Increasing Development Assurance for System and Software Development with Validation and Verification Using ASSERT™

GE Aviation Systems LLC-Craig McMillan, Mark Stephens, Daniel Russell
GE Global Research Center-Andy Crapo, Michael Durling, Meng Li, Abha Moitra
Published 2019-03-19 by SAE International in United States
System design continues to trend toward increasing complexity as more functionality is added to aviation systems and the level of automation is increased. Since exhaustive validation and verification of this functionality becomes increasingly difficult, reliance on development assurance is needed to provide confidence that errors in requirements, design and implementation have been identified and corrected. To address this need for increased development assurance, GE is introducing a tool called ASSERT™ (Analysis of Semantic Specifications and Efficient generation of Requirements-based Tests). The system developer uses this tool to capture requirements in an unambiguous way with built-in semantic error checking. The requirements analysis engine is then used to assist in requirements validation to identify common problems which may include requirements that conflict with one another, requirements that do not fully specify the behavior of a function, requirements that are not independent of one another, and requirements that are either always true or false. Having unambiguous and complete requirements also enables the tool to consistently generate a complete set of requirements-based test cases and procedures to ensure the…
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